There verses are such a nice illustration of the fact that the temple is not supposed to be like the “sacred mysteries” of other churches. The endowment may have different levels of meaning, but that is very different than saying that the endowment either doesn’t really have any specific intended meaning or saying that the endowment is simply not for regular church members to understand.
D&C 76:5 For thus saith the Lord—I, the Lord, am merciful and gracious unto those who fear me, and delight to honor those who serve me in righteousness and in truth unto the end.
6 Great shall be their reward and eternal shall be their glory.
7 And to them will I reveal all mysteries, yea, all the hidden mysteries of my kingdom from days of old, and for ages to come, will I make known unto them the good pleasure of my will concerning all things pertaining to my kingdom.
8 Yea, even the wonders of eternity shall they know, and things to come will I show them, even the things of many generations.
9 And their wisdom shall be great, and their understanding reach to heaven; and before them the wisdom of the wise shall perish, and the understanding of the prudent shall come to naught.
10 For by my Spirit will I enlighten them, and by my power will I make known unto them the secrets of my will—yea, even those things which eye has not seen, nor ear heard, nor yet entered into the heart of man.
I would not be surprised if some people I know even quite rightly believe that through the temple instruction the Lord can and will reveal to us the mysteries of His Kingdom.